Among pneumatic fenders, there are vertical pneumatic fenders with a weight connected to the bottom of the fender body, and with a predetermined quantity of ballast water stored within an interior space (for example, see Japanese Unexamined Patent Application Publication No. H11-117261A). The vertical pneumatic fender is maintained in a stable attitude by the balance between the vertical downward force of the weight and the ballast water stored in the interior space and the buoyancy force acting on the fender body.
The weight is connected to a fitting on the bottom of the fender body either indirectly via a chain or directly using a bolt or the like. When moored in a harbor where the water is insufficient, the weight of the vertical pneumatic fender repeatedly impacts the sea floor when there are large vertical oscillations. Alternatively, when the vertical pneumatic fender is inappropriately handled such as by towing with the weight attached, an excessive external force can be applied to the chain or bolt that connects the weight to the fitting. In these cases damage can occur to the chain, the bolt, or the connector (fitting) to which these are connected, causing the problem that the weight drops to the sea floor.
The weight that has dropped to the sea floor becomes waste as it is. Also, the fender from which the weight has fallen immediately greatly loses the vertical balance, and thus it is not possible to maintain its original installed attitude. In other words, the problem occurs that the intended functionality of the fender cannot be ensured due to the vertical pneumatic fender floating in a horizontal attitude.